Dredger



July 21,1964 J. B. BJORKLUND DREDGER 4 Sheets-Sheet 1 Filed Dec. 5, 1962 AT-rozA Ey July 21, 1964 J. B. BJORKLUND 3,141,561

DREDGER Filed Dec. 3, 1962 4 Sheets-Sheet 2 FIG-.2

July 21, 1964' J. B. BJORKLUND 3,

DREDGER Filed Dec. 3, 1962 4 Sheets-Sheet 3 July 21, 1964 J. B. BJORKLUND 3,141,561

DREDGER Filed Dec. 3, 1962 4 Sheets-Sheet 4 United States Patent 3,141,561 DREDGER John Bertil Bjiirklund, Nyholm, Tibro, Sweden Filed Dec. 3, 1962, Ser. No. 241,645 Claims priority, application Sweden Dec. 11, 1961 Claims. (Cl. -2l4138) This invention relates to dredgers, and more particularly to small lightweight dredgers of the tractor driven type.

During recent years small dredging machines, hydraulically operated and in many cases tractordriven have been employed to an increasing extent. This may be explained by the fact that, compared with large size dredges on tracks, the smaller dredging units are easier to transport between different working places and show better economy of operation. They are particularly adapted for trenching, excavating in narrow passages and for loading operations.

Previous types of light-weight dredgers have had certain shortcomings, such as low excavating capacity and limited movement in the horizontal as well as vertical plane.

The general object of this invention is to provide a dredger having great excavating capacity in relation to its weight and a wide range of movement both in the horizontal and vertical plane.

A dredger embodying the invention will now first be fully described with reference to the accompanying drawing and the features forming the invention will then be pointed out in the appended claims.

In the drawing:

FIG. 1 is a side elevation view of the dredger;

FIG. 2 is a section on the line II-II of FIG. 1, showing the arrangement for swinging the derrick in the horizontal plane, and with the derrick aligned with the longitudinal axis of the tractor; and

FIGS. 3 and 4 are views similar to FIG. 2, but showing the derrick swung into the two outermost positions obtainable, for example, during loading.

As appears from FIG. 1, the dredger comprises a derrick holder 16 mounted for pivoting a vertical axis by means of pins 28 in a stand 26 mounted on a tractor. The stand 26 (FIG. 2) is provided with legs 27 supporting the tractor while the excavating operation is carried out. A derrick 11 pivotally supported at its lower end by the holder carries at its free end a jib 12 with a scoop 13. The derrick supports a cross-link 14 having one end pivotally connected to the piston rod of a hydraulic cylinder 16 which is pivotally connected at its lower end to the derrick 11 adjacent the pivot point of the derrick. A hydraulic cylinder 15 is pivotally connected to the holder 10 at a point located above the point of attachment of the derrick, the piston rod 24 of the said cylinder 15 being connected to a linkage comprising two link members 21 and 22. One of these members, 21, is hingedly connected with cross-link 14, and the other member, 22, with the derrick 11.

For operating the scoop 13, there is provided on the derrick a hydraulic cylinder 18 having its piston rod 19 pivotally connected with a cross-link 23 mounted on the jib 12. The said cross-link 23 is pivotally .connected with the link 20, the other end of which is pivotally supported on the upper edge of the scoop 13. The two cross-links 14 and 23 are connected together by means of a pull rod 17.

For etfecting the swinging of the derrick 11 and its holder 10 in the horizontal plane, as shown in FIG. 2, a link rod 29 is provided with one end 30 pivotally connected to a forward projecting portion of the holder 10 and with its other end 31 pivotally connected to an arm 33 swingably mounted at 32 on the stand 26. A doubleacting hydaulic cylinder 34 is provided with one end 35 swingably mounted on the stand and with its piston rod end pivotally connected at 36 to the central portion of the link rod 29. The said cylinder 34 may, of course, also be mounted with the piston rod end connected to the stand and with the cylinder end connected to the link rod, but this would not influence the functioning of the unit.

In FIG. 3 the piston rod of the cylinder 34 is shown in extended position, thereby swinging the holder 10 and derrick 11 in anticlockwise direction about the mounting point 28 of holder 10 in the stand 26. When the piston rod is drawn in, the elements 10 and 11 will be swung into the opposite outermost position, as appears from FIG. 5.

The hydraulic cylinders as described above are of the double-acting type and preferably adapted to be controlled individually. The advantage of the unit according to the invention lies in the fact that, due to the decrease in load on the outer end of the derrick, its weight could be reduced. At the same time, a considerable tractional force is exerted on the jib because both cylinders 15 and 16 are connected with the cross-link 14 mounted on the derrick. As a further advantage it may be noted, that the derrick is lifted automatically whilst the scoop is being emptied. Furthermore, the dredger can be swung in the horizontal plane within an angle of about 200 degrees, which was not possible with previously known arrangements.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A dredger comprising a holder with a derrick mounted thereon which is swingable in the vertical and horizontal plane and on which is pivotally mounted a jib carrying a pivotally mounted scoop adapted to be actuated by a hydraulic cylinder via a cross-link pivotally mounted on the jib and a second link, characterized in that the derrick and the jib can be operated by two hydraulic cylinders for swinging the derrick in the vertical plane, one of the said cylinders mounted for vertical swinging in the holder, and the second cylinder mounted for vertical swinging on the derrick, the piston rod of one of the said cylinders mounted in a link means comprising two members whereof one is in pivotal connection with a second cross-link pivotally carried on the derrick and the other link member is in pivotal connection with the derrick, the piston rod of the second hydraulic cylinder being pivotally connected to the cross-link.

2. A dredger according to claim 1, characterized in that the hydraulic cylinder fastened in the holder for vertical swinging is mounted in a point above the derrick on the holder.

3. A dredger according to claim 2, characterized in that the cross-links are in pivotal connection with one another by means of a pull rod.

4. A dredger according to claim 3, characterized in that the link for operating the scooping is pivotally connected to the upper edge of the scoop.

5. A dredger according to claim 1, characterized in that for swinging the derrick in the horizontal plane a special hydraulic cylinder actuates a link system comprising a link rod pivotally connected between the derrick and a swingable arm mounted in the stand, in which the said cylinder is pivotally mounted at one end while its other end is swingably mounted in the stand, the points of mounting mutually arranged such, that by retracting or projecting outermost positions.

References Cited in the file of this patent UNITED STATES PATENTS Pilch Sept. 20, Britton Dec. 6, Holopainen Oct. 30, Way Apr. 22, Przybylski May 13, Wills Sept. 8, Gofner Nov. 24, Mork Mar. 8, Russell May 10,

FOREIGN PATENTS Great Britain Aug. 29, Great Britain Oct. 30, 

1. A DREDGER COMPRISING A HOLDER WITH A DERRICK MOUNTED THEREON WHICH IS SWINGABLE IN THE VERTICAL AND HORIZONTAL PLANE AND ON WHICH IS PIVOTALLY MOUNTED A JIB CARRYING A PIVOTALLY MOUNTED SCOOP ADAPTED TO BE ACTUATED BY A HYDRAULIC CYLINDER VIA A CROSS-LINK PIVOTALLY MOUNTED ON THE JIB AND A SECOND LINK, CHARACTERIZED IN THAT THE DERRICK AND THE JIB CAN BE OPERATED BY TWO HYDRAULIC CYLINDERS FOR SWINGING THE DERRICK IN THE VERTICAL PLANE, ONE OF THE SAID CYLINDERS MOUNTED FOR VERTICAL SWINGING IN THE HOLDER, AND THE SECOND CYLINDER MOUNTED FOR VERTICAL SWINGING ON THE DERRICK, THE PISTON ROD OF ONE OF THE SAID CYLINDERS MOUNTED IN A LINK MEANS COMPRISING TWO MEMBERS WHEREOF ONE IS IN PIVOTAL CONNECTION WITH A SECOND CROSS-LINK PIVOTALLY CARRIED ON THE DERRICK AND THE OTHER LINK MEMBER IS IN PIVOTAL CONNECTION WITH THE DERRICK, THE PISTON ROD OF THE SECOND HYDRAULIC CYLINDER BEING PIVOTALLY CONNECTED TO THE CROSS-LINK. 